1. Field of the Invention
The present invention relates to vaults and more particularly to subterranean vaults. The present invention provides lightweight, water-tight construction in a vault and venting and purging features. All of the novel qualities extend life of batteries being stored within the novel vault.
2. Description of the Prior Art
Electrical equipment is frequently stored in enclosures such as cabinets or vaults so that the equipment is located proximate premises served by the equipment, while enabling the equipment to remain substantially inaccessible to the public. In particular, telephone utility companies store batteries for operating the telephone system. Cabinets and vaults are useful in protecting batteries against animals and human vandals and thieves, but are prone to deleterious influences shortening battery life.
The useful life of batteries is reduced by exposure to elevated temperatures and to water. Battery manufacturers supplying batteries typically specify that the environment of the battery average no higher than 77.degree. F. over time and not to exceed 92.degree. F. at any time. Therefore, it is desirable to limit temperatures within and to deny infiltration of water into any enclosure housing batteries. Water may infiltrate by seepage in the liquid state and also by circulation of air laden with humidity into the enclosure. Water vapor will condense when temperatures cool, and will come to rest on battery surfaces, ceiling surfaces above the batteries, and on battery racks, with eventual drippage onto the batteries.
Operation of acid using batteries typically releases hydrogen into the air due to electrolysis of water from the acid. Hydrogen is notoriously combustible, and must be vented to mitigate hazards of fire and explosions. Therefore, it is not feasible to fully seal the enclosure to eliminate infiltration by water. Simultaneously, the enclosure must limit its internal temperature.
Underground vaults for protecting electrical equipment has been proposed in the prior art. Underground vaults are shown in U.S. Pat. Nos. 3,390,225, issued to Robert O. Couch et al. on Jun. 25, 1968, 3,420,943, issued to Herbert D. Short on Jan. 7, 1969, and 4,709,120, issued to Dean C. Pearson on Nov. 24, 1987. The vault of Pearson comprises inner and outer concentrically disposed chambers, the inner chamber being wooden and the outer chamber being metallic. Pearson's vault is ventilated by a duct having a controllable damper. By contrast, the vault of the present invention comprises a single chamber formed from fiberglass reinforced concrete, and has a tightly controlled venting and air purging system.
Short provides a concrete vault having a raised floor or stand for supporting a transformer. This vault is cooled by a wind powered ventilating fan mounted atop an exhaust stack. By contrast, the concrete vault of the present invention is impervious to water and is effectively closed to constant communication with the atmosphere by its venting and air purging system.
Couch sets forth an inexpensive construction wherein a metallic pipe or the like is arranged vertically, with one end resting on or embedded within a concrete pad. This invention lacks the continuous concrete construction and venting and air purging system of the present invention.
U.S. Pat. No. 4,949,626, issued to Douglas W. Townsend et al. on Aug. 21, 1990, describes a sump assembly designed to expel both water and radon gas from a building. The sump comprises a pit covered by a hood. The hood encloses both a pump for ejecting accumulated water and a fan for forcibly venting radon gas. This device is far from air and water tight, as is the present invention. The device of Townsend et al. further lacks the fiberglass reinforced housing and air purging system of the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.